<i>In Situ</i> Formed Ti/Nb Nanocatalysts
within a Bimetal 3D MXene Nanostructure Realizing Long Cyclic Lifetime
and Faster Kinetic Rates of MgH<sub>2</sub>
Magnesium hydride (MGH) is a high-capacity and low-cost
hydrogen
storage material; however, slow kinetic rates, high dehydrogenation
temperature, and short cycle life hindered its large-scale applications.
We proposed a strategy of designing novel delaminated 3D bimetal MXene
(d-TiNbCTx) nanostructure
to solve these problems. The on-set dehydrogenation temperature of
MGH@d-TiNbCTx composition
was reduced to 150 °C, achieving 7.2 wt % of hydrogen releasing
capacity within the range of 150–250 °C. This composition
absorbed 7.2 wt % hydrogen within 5 min at 200 °C and 5.5 wt
% at 30 °C within 2 h, while the desorption capacity (6.0 wt
%) was measured at 275 °C within 7 min. After 150 cycles at 250
°C, the 6.5 wt % capacity was retained with negligible loss of
hydrogen content. These results were attributed to the catalytic effect
of in situ-formed TiH2/NbH2 nanocatalysts, which lead to dissociate the Mg–H bonds and
promote of kinetic rates. This unique structure paves great opportunities
for designing of highly efficient MGHs/MXene nanocomposites to improve
the hydrogen storage performance of MGHs